Bathymetric data derived from a multipectral World View-2 satellite
image mosaiced to provide near complete coverage of nearshore
terrain around the islands. Bathymetry values shallower than ~20 m were
derived by gauging the reletive attenuation of coastal, blue, green and yellow
spectral radiance as a function of depth. A multiple linear regression analysis
of coastal, blue, green and yellow band spectral values against depth determined
the variables of y-intercept, coastal,blue, green and yellow slope values.
Variables then used in multivariate slope intercept formula to derive
depth. Variables were adjusted to improve the statistical accuracy and
spatial coverage of the final derived bathymetry product. Digital image
processing to derive depths conducted with the ENVI 4.8 software program
while data editing and integration was performed using ArcGIS 10. This
data set is for the shelf environment of Ni'ihau Island,
Hawaii.

Purpose:

The data were derived in support of NOAA Coral Reef Conservation
Program goals. Goal 1 is to map all U.S. Coral Reef Ecosystems.
This data set specifically addresses Objective 1 and 4: to develop
high-resolution benthic maps and to characterize priority deep
water reefs and associated habitats. This derived bathymetry provides a
GIS layer with expanded spatial coverage that may be used for benthic and
essential fish habitat characterization, and for the study of geologic features.
By combining the dataset with other bathymetry, backscatter, derivatives,
and in situ data, they collectively compose benthic habitat maps
designed to be used to understand and predict shallow depth (0m to 150m)
benthic habitats for organisms that inhabit coral reef ecosystems.

Supplemental_Information:

Geographic Information System (GIS) project and National Ocean Service's
(NOS) coral mapping activities. Orthographically corrected World View-2 Imagery
was provided by USGS, State of Hawaii and USDA. The metadata for this World View-2
imagery is documented in the original product metadata,
10JAN02213954-M3XM-052386144080_01_P001.(<http://www.soest.hawaii.edu/pibhmc/>)

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20100102

Ending_Date: 20100102

Currentness_Reference: ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -160.254655

East_Bounding_Coordinate: -155.254655

North_Bounding_Coordinate: 22.0298068

South_Bounding_Coordinate: 17.0298068

Keywords:

Theme:

Theme_Keyword_Thesaurus: CRCP Project

Theme_Keyword:

Benthic Habitat Mapping and Characterization in the Pacific Islands Region

These data are not to be used for navigation
purposes. Please acknowledge NOAA Pacific Islands Fisheries
Science Center, the Joint Institute for Marine and
Atmospheric Research (JIMAR) University of Hawaii as the
sources of this information.

Data are collected for resource
management and research purposes and are tested for
internal consistency; however, no effort is made to compare
these data to external references or to other published data.

Logical_Consistency_Report:

These data are believed to be logically
consistent though no tests were performed

Multiple tools in ENVI 4.8 were used to complete the following
processing steps: Data conversion from digital number to radiance,
correction for atmosphere and water surface reflection, masking of
non-applicable values, and bathymetric derivation using variables
from multiple linear regression analysis. Multiple tools in
ArcGIS 10 were used for dataset integration and to extract values
for the multiple linear regression analysis and subsequent error
analyses. The Microsoft program Excel was used for the multiple
linear regression analysis to provide original variables for depth
derivation. The multivariate slope intercept formula used to
derive depth was Depth=Yint+(Mcoastal)(Xcoastal)+(Mblue)(Xblue)+(Mgreen)(Xgreen)+(Myellow)(XYellow).
Three products were derived, all from the original image 10JAN02213954-M3XM-052386144080_01_P001,
which was devided in three sections SW, N, E Niihau.The MLR variables for SW Niihau
were Yint=70.04351364, Mcoastal=-0.411613009, Mblue=-1.30485119, Mgreen=-1.031082842,
Myellow=0.786152945, for E Niihau were Yint=-24.38584123, coastal=-184.3932459,
Mblue=-403.3462551, Mgreen=1135.36388, Myellow=-246.50699213 and for N Niihau were
Yint=-33.44035302, Mcoastal=0.253885458, Mblue=-0.727701937, Mgreen=1.185332714, Myellow=0.841131904
The derived bathymetry mosaics from each image were in turn mosaiced
giving the data from SW Niihau priority over N Niihau due to its statistaclly
higher accuracy.
A detailed description of all processing steps
and an error analysis of each derived bathymetry grid used is
available upon request.

These data are not to be used for navigational purposes.
NOAA makes no warranty regarding these data, expressed or implied,
nor does the fact of distribution constitute such a warranty.
NOAA cannot assume liability for any damages caused by any errors
or omissions in these data, nor as a result of the failure of
these data to function on a particular system.